194 NEW DEVELOPMENTS IN HIGH VACUUM APPARATUS. 



is carried into the low-pressure turbine and does useful work. The exhaust steam devel- 

 ops a horse-power with about double the consumption of high-pressure steam, which is not 

 a bad performance. In other words, in, the complete expansion turbine, with high-pressure 

 steam, we get a horse-power for about 11.5 pounds. With the exhaust steam we develop a 

 horse-power for about, say, 25 pounds, so that the exhaust steam going into the low-pressure 

 turbine develops quite a good deal of power. 



The steam-air ejector is a new device to most operating engineers, and for that reason 

 we were very careful to provide the operating engineers of our vessels with suitable infor- 

 mation as to the practical operation and handhng of these air ejectors. We prepared a com- 

 plete set of practical operating instructions, which were as practical as we could make them, 

 and furnished them to the operating engineers of our vessels. This was in addition to the 

 instructions which were prepared by the makers of the apparatus, and I think that the sup- 

 plying of this information had a good deal to do with the success which this apparatus has 

 met, because we have had absolutely no trouble whatever with any single ship we turned 

 out with this apparatus. 



It is very important also to provide instructions for the draughtsmen and designers in 

 handling a new type of apparatus of this character, and we provided instructions for our 

 drawing office which took care of the various details in a proper way. 



In closing, it might be interesting for Mr. Kothny to state the number of vessels which 

 have been fitted with air ejectors of this and other types, if he has that information; also 

 the types of in'fetallations, whether engines or turbines, and the total horse-power of steam 

 vessels which have been equipped with air ejectors. 



Mr. Ernest H. B. Anderson, Member: — There are one or two points I should like to 

 draw attention to. It is rather surprising that the author did not draw attention to the 

 work of Sir Charles A. Parsons, who invented the vacuum augmentor in the year 1903, for 

 both the Radojet and the Le Blanc air ejector are based on the same principle. 



The Parsons vacuum, augmentor is in use in practically all the large turbine-driven bat- 

 tleships of the American Navy, and in most of the destroyers. 



The great feature about the vacuum augmentor lies in the fact that it is used in con- 

 junction with the ordinary single-acting wet-air pump, and the air pump is so arranged in 

 the engine-room that it can be used with or without the augmentor. 



In all turbine installations it is of vital importance that the turbines are at all times 

 drained thoroughly and kept clear of water, but I note that the author does not take up this 

 question, although it bears a very essential relation to this apparatus. 



Experience has shown that the turbo-condensate pumps do not operate properly if vapor 

 instead of water passes into the suction pipe, and for this reason it is necessary, in cases where 

 this form of pump is fitted, to install an ejector to deal Avith the turbine drains. This is not 

 a desirable feature, and experience has shown it is necessary that the drainage from the low- 

 pressure turbine exhaust will be entirely automatic. 



It seems to me that the use of high-speed turbo-condensate pumps will soon be super- 

 seded by the regular twin-beam., single-acting, wet-air pump, largely for the reason that this 

 type of pump can be subjected to all kinds of rough usage without showing signs of distress. 



The President: — Are there any further comments? If not, we will ask Mr. Kothny 

 to make such rejoinder as he desires. 



